Sunday 8th September, 2013
9:30am to 9:50am
GPS and overhead imagery do not work in tunnels. Harry Beck's Tube map has taught Londoners that trains only travel at multiples of 45 degrees, but railways and pipelines below ground are rarely simple or straight. Despite this, OSM often has greater coverage with accuracy than other available maps! This talk covers how underground surveying can be done, from the hunt for ventilation shafts and escalator entrances, to how the original tunnels were surveyed (horizontally) and levelled (vertically) a century earlier. Before GPS there were theodolites and trigonometry, but modern surveying has the gyrotheodolite and computers. Join us as we venture underground, deep beneath Berlin, Helsinki, London and the Channel Tunnel.
9:50am Use of UAV in Haiti by Frederic Moine
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